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What: Shares of multimedia semiconductor designer Trident Microsystems (Nasdaq: TRID) fell as much as 19% after the company lowered its expectations for fourth-quarter revenue.

So what: Trident's previous guidance for the fourth quarter was for revenue of $130 million to $140 million and a non-GAAP operating loss of $4 million to $8 million. According to the updated guidance, the actual results won't even sniff the previous expectations. The company now calls for revenue of $115 million to $120 million and a non-GAAP operating loss of $18 million to $22 million. In its statement, the company blamed weaker-than-expected sales to both TV and set-top box customers.

Now what: It doesn't sound like the fourth quarter was a fluke: Trident also said that similar customer trends would hit the first-quarter results even harder. Though the company has recently faced losses and cash burn, there have been hopes that it could turn things around. The company does still sport a debt-free balance sheet with a considerable amount of cash, but with the prospect of more potholes, this stock seems as speculative as ever.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his Motley Fool CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy is looking forward to a great 2011.